This invention relates to compounds, compositions and methods for inhibiting lipoxygenase enzymes.
The lipoxygenases are a family of enzymes which catalyze the oxygenation of arachidonic acid. The enzyme 5-lipoxygenase converts arachidonic acid to 5-hydroperoxyeicosatetraenoic acid (5-HPETE). This is the first step in the metabolic pathway yielding 5-hydroxyeicosatetraenoic acid (5-HETE) and the important class of potent biological mediators, the leukotrienes (LTs).
A variety of biological effects are believed to be associated with these products from lipoxygenase metabolism of arachidonic acid, and they have been implicated as mediators in various disease states. For example, the LTs C.sub.4 and D.sub.4 are potent constrictors of human airways in vitro, and aerosol administration of these substances to non-asthmatic volunteers induces broncho-constriction. LTB.sub.4 and 5-HETE are potent chemotactic factors for inflammatory cells such as polymorphonuclear leukocytes. They also have been found in the synovial fluid of rheumatoid arthritic patients. Leukotrienes have also been implicated as important mediators in allergic rhinitis, psoriasis, adult respiratory distress syndrome, Crohn's disease, endotoxin shock, and ischemia induced myocardial injury among others. The biological activity of the LTs has been reviewed by Lewis and Austen (J. Clinical Invest. 73,89, 1984 and by J. Sirois (Adv. Lipid Res. 21, 78, 1985).
Thus, lipoxygenase enzymes are believed to play an important role in the biosynthesis of mediators of asthma, allergy arthritis, psoriasis, and inflammation. Blocking the activity of these enzymes will likely interrupt the pathological pathways believed to be involved in these disease states.